*{
    margin: 0;
    padding: 0;
}

body{
    height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;
}
/* button style start */
.login{
    position: relative;
    border: none;
    outline: none;

    width: 12rem;
    height: 5rem;
    border-radius: 5rem;
    background-color: #000;
    color: #fff;
    font-weight: bold;
    font-size: 1.5rem;
    box-shadow: 0 8px 28px black;
    cursor: pointer;

    transition: .5s;
}

.active.login{
    width: 5rem;
    color:transparent;
}

/* button style end */

/* loading style start */
.loading{
    opacity: 0;
    transition: .5s;
}

.active .loading{
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%,-50%);

    width: 70%;
    height: 40%;

    display: flex;
    justify-content: space-around;  
    align-items: flex-end;
    opacity: 1;
}

.active .loading div{
    width: .3rem;
    height: .3rem;
    border-radius: 50%;
    background-color: #fff;

    animation: .9s loading ease-in-out infinite alternate;
}

@keyframes loading{
    to{
        transform: translate(0, -1rem);
    }    
}

.active .loading div:nth-child(2){
    animation-delay: .2s;
}

.active .loading div:nth-child(3){
    animation-delay: .4s;
}

.verity .loading{
    opacity: 0;
}
/* loading style end */

/* checkmark style start */
.checkmark{
    position: absolute;
    left: 50%;
    top: 56%;
    transform: translate(-50%,-50%);
    stroke-width: 2px;
    /* 利用stroke的虚线和偏移值达到加载的动画效果 */
    stroke-dasharray: 36px;
    stroke-dashoffset: 36px;
}

.verity .checkmark{
    animation: .6s show forwards;
    animation-delay: .4s;
}

@keyframes show{
    to{
        stroke-dashoffset: 0;
    }
}
/* checkmark style end */

